The invention discloses a power management device. The device comprises a CPU chip, a first control chip, a second control chip, an inversion module, a main/standby power switching module, a power module AC, an alarm access control output module, a UPS input module, a standby battery module, a commercial power detection module, a communication equipment module, a monitoring system module, a UPS battery detection module, an alarm battery module, an access control battery module and a standby monitoring module. The first control chip and the second control chip are both electrically connected with the CPU chip, the inversion module is composed of a 220V connection output interface, a 12V battery input interface and a control switch, and the main/standby power switching module is composed ofa standby accessing interface, a main power accessing interface and an alternating current output interface.